Embodiments of the inventive subject matter generally relate to the field of power spectral density, and, more particularly, to power spectral density shape for transmitted signals.
Communication technology is evolving to utilize multi-frequency transmissions over a communications medium. For example, in many technologies, such as powerline communications, a transmitting device may send signals via a plurality of frequencies to one or more other devices coupled to the communications medium. Other medium and technologies may also use multi-carrier transmissions in which multiple frequencies are used over a communication channel.
A power spectral density (PSD) shape refers to power distribution for signals over different frequencies. For example, power may be reduced for a subset of the frequencies used over the communication channel. Reducing power for particular frequencies may also be referred to as “notching” or “filtering.” In some communications medium, certain frequencies are required to be notched, and may be referred to as notched, reserved, or rejection bands.